package cn.org.xuanguang.kepler.hormos.rdb.jpa;


import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static cn.org.xuanguang.kepler.hormos.rdb.jpa.EnumType.ORDINAL;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Specifies that a persistent property or field should be persisted
 * as a enumerated type.  The <code>Enumerated</code> annotation may
 * be used in conjunction with the <code>Basic</code> annotation, or in
 * conjunction with the <code>ElementCollection</code> annotation when the
 * element collection value is of basic type.  If the enumerated type
 * is not specified or the <code>Enumerated</code> annotation is not
 * used, the <code>EnumType</code> value is assumed to be <code>ORDINAL<code>.
 *
 * <pre>
 *   Example:
 *
 *   public enum EmployeeStatus {FULL_TIME, PART_TIME, CONTRACT}
 *
 *   public enum SalaryRate {JUNIOR, SENIOR, MANAGER, EXECUTIVE}
 *
 *   &#064;Entity public class Employee {
 *       public EmployeeStatus getStatus() {...}
 *       ...
 *       &#064;Enumerated(STRING)
 *       public SalaryRate getPayScale() {...}
 *       ...
 *   }
 * </pre>
 * 最简单的方式是使用@Enumerated注解来指定枚举应该如何映射到数据库。默认情况下，枚举值会被映射为字符串（EnumType.STRING），但也可以选择映射为整数（EnumType.ORDINAL）。
 *
 * @see Basic
 * @see ElementCollection
 * @since Java Persistence 1.0
 */
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface Enumerated {

    /**
     * (Optional) The type used in mapping an enum type.
     */
    EnumType value() default ORDINAL;

    /**
     * 映射的属性名
     *
     * @return
     */
    String mapping() default "";
}

